Thank you Sylvain and Tuomo for your responses. If found another solution which gave me the added feature of that clients stay in their places when sending SIGUSR1 to ion.
In my .xsession I have.
${MKDIR} -p ${HOME}/.ion3/osten
cp -f ${HOME}/.dot/ion/osten_layout.lua ${HOME}/.ion3/osten/saved_layout.lua
/pkg/ion/3/bin/ion3 -conffile ${HOME}/.dot/ion/osten.lua -session osten
So I initialize the screen to the layout I want and then let ion
handle it.
